Reliability of panoramic radiography in predicting proximity of third molars to the mandibular canal: A comparison using cone-beam computed tomography

Abstract

Purpose The purpose of this study was to analyze the reliability of 7 panoramic radiographic signs for predicting proximity of the root apices of mandibular third molars to the mandibular canal using cone-beam computed tomography and to correlate these findings with the Pell and Gregory and the Winter classification systems. Materials and Methods An observational, cross-sectional, descriptive study was conducted on 74 patients with bilateral impacted mandibular third molars. Four panoramic radiographic signs were observed in the tooth root (darkening, deflection, and narrowing of the root apices, and bifid apices), and another 3 in the mandibular canal (diversion, narrowing, and interruption of the mandibular canal). Cone-beam computed tomography images were analyzed to identify disruption and diversion of the mandibular canal and root deflection. Results Binary logistic regression showed that only 4 of the 7 panoramic radiographic signs were able to predict proximity of the root apices of the mandibular third molars to the mandibular canal: darkening of the root, deflection of the root, narrowing of the root, and interruption of the mandibular canal ( P <0.05). Conclusion Darkening, deflection, and narrowing of the root, in tandem with the interruption of the mandibular canal on panoramic radiographs, indicate that cone-beam computed tomography should be performed when planning the extraction of impacted mandibular third molars. Proximity between mandibular third molars and the mandibular canal is correlated with the Winter classification.

Risk factors for external root resorption of maxillary second molars associated with third molars

“…In mandibular M3s, superimposition of M3 onto the mandibular canal was considered as a risk factor of close contact, and several signs of superimposition such as darkening of the root or loss of the cortical line of the canal on panoramic images were also evaluated. 17 18 19 This study revealed superimposition to be a major risk factor, underscoring the need for further research on maxillary M3s. Although previous studies did not address superimposition, a few studies revealed that direct contact of M3 with the root surface of M2 is a major risk factor for ERR.…”

Association of indications for mandibular third molar coronectomy and the Pell and Gregory and the Winter classification systems

“…Most previous work using these classi cation systems in relation to a coronectomy has focused on root migration of mandibular third molars following a coronectomy. A few studies have used these classi cation systems to assess the diagnostic value of panoramic radiographs in predicting a true relationship between the mandibular third molar and the IAN [16, 17,19,20]. In those investigations, the impaction pattern was compared with a gold standard, either a CT or cone-beam CT scan.…”

Análisis de terceros molares y sus estructuras anatómicas adyacentes mediante CBCT: meta-análisis

“…Una imagen 3D permite observar tres planos anatómicos a diferencia de una imagen 2D que muestra únicamente dos planos de una estructura tridimensional. El profesional debe tener en cuenta que la presencia de oscurecimiento, desviación o estrechamiento de la raíz junto con la interrupción del CDI en una RP determina una nueva toma radiográfica, para la cual el método de elección será un estudio CBCT (Nunes et al, 2021).…”

“…3.6 Fiabilidad de la radiografía panorámica para predecir la proximidad de los terceros molares al canal mandibular: una comparación mediante tomografía computarizada de haz cónico Otro estudio realizado por Nunes y Cols., en el 2021 analiza la confiabilidad de los estudios radiográficos (RP y CBCT), en el cual se buscó observar la posición de los ápices dentales y su relación con el CDI. Sin embargo, las RP presentan una distorsión referente a las medidas lineales y superposición de estructuras; por lo cual el método radiográfico de mayor precisión es una CBCT debido a los múltiples planos que presenta, además este estudio clasificó de 3 maneras la posición de los 3MM con sus estructuras adyacentes según (Nunes et al, 2021):…”

“…-Posicionamiento de los dientes según la clasificación de Pell y Gregory Este artículo sugiere que la presencia de un área radiográfica con oscurecimiento, desviación o estrechamiento de la raíz, en conjunto con la interrupción del CDI en las RP sugieren la utilización de CBCT (Nunes et al, 2021).…”